Reversible drive



Allg- 5, 1958 A. D. BROWN, JR., ETAL 2,845,820

REVERSIBLE DRIVE Filed Oct. '7, 1953 INVENTORS ARLING DIX. BROWN JR.

LEO F. VALENTI RNEY United States Patent O REVERSIBLE DRIVE Arling Dix Brown, Jr., East Cleveland, and Leo F. Valenti, Garfield Heights, Ohio, assignors to Clevite Corporation, Cleveland, Ohio, a corporation of Ohio Application October 7, 1953, Serial No. 384,632

7 Claims. (Cl. 74-780) This invention relates to a reversible drive.

It is an object of the present invention to provide a novel drive which may be reversed in direction within a very short time interval.

It is also an object of the present invention to provide a novel reversible drive in which the reversing portion of the drive has low inertia, thereby enabling the drive to be reversed with a short time interval.

Although the drive of the present invention is of general utility wherever a drive capable of quick reversal is desired, it has been found to be particularly useful in connection with a motor driven surface roughness analyzer. In the surface roughness analyzer a stylus is moved in very short strokes back and forth across the surface to be analyzed. In one instrument of this type the stroke of the stylus is only inch and the stylus moves at a speed of Mz inch per second. With such an instrument it is not feasible to use a reversible motor to reverse the direction of movement of the stylus because such motors, due to relatively high inertia, require a time interval of the' order of magnitude of 1A second to reverse, which is inordinately long for applications of this type. This problem of quick reversal is satisfactorily resolved in the present invention by the provision of a novel reversible drive in which the reversing parts have low inertia, thereby enabling the drive to reverse quickly. Such a reversible drive constructed in accordance with the following description and the accompanying drawing has been found to be capable of reversing within the extremely short time interval of about .015 second, thereby rendering it particularly useful in connection with surface roughness analyzers of the type mentioned above.

The foregoing, as Well as other and further objects and advantages of the present invention will be apparent from the following description of the preferred embodiment thereof, which is illustrated in the -accompanying drawing. y

In the drawing:

Figure 1 is a perspective view of the drive showing the parts arranged to drive the output shaft in the forward direction;

Figure 2 is a longitudinal section through the mechanism during the forward drive;

Figure 3 is a perspective view of the drive showing the parts arranged to impart a reverse drive to the output shaft; and

Figure 4 is a longitudinal section through the drive when the reverse drive is imparted to the output shaft.

Referring to the drawings, in the preferred embodiment of the present invention there is provided a rotary input shaft which rotates at all times in the direction indicated by the arrow (-counterclockwise in the drawing). Shaft 10 at. its inner end carries a pinion 11 which mesheswith a relatively large input gear 12 mounted freely on a rotatable shaft 13. A driving bevel gear 14 is integral with gear 12 at one side thereof and rotates in unison therewith.

At its opposite side, input gear 12 carriesk a friction lCC disk 15 positioned to be engaged selectively by a similar friction disk 16 carried by an annular armature 17. Armature 17 is formed with a central opening 18 through which shaft 13 extends freely. At one end, at the opening 18 the armature is formed with an annular, radially inwardly projecting shoulder 19 to which is secured integrally a cross pin 20 which extends through an elongated narrow slot 20a in shaft 13. With this arrangement armature 17 and shaft 13 are coupled together for rotation in unison, while armature 17 is capable of limited sliding movement axially along shaft 13. A coil spring 21 is under compression between this shoulder on the armature and a hub 22 carried by shaft 13 and normally biases the armature to the right in the drawing to position friction disk 16 tightly against friction disk 15, thereby establishing a friction coupling from input gear 12 to shaft 13 to rotate the latter in response to rotation of gear 12.

For stopping the rotation of shaft 13 `and de-coupling it from gear 12 there `is provided an electromagnet 23 mounted on a supporting Wall 24 and positioned adjacent armature 17. Electromagnet 23 when energized is capable of attracting armature 17 against the bias of spring 21 to separate friction disk 16 from the friction disk 15, thereby stopping the rotation of the armature and shaft 13.

At the front side of driving bevel gear 14 the shaft 13 is formed with a cross drilled hole 25 which snugly receives an elongated cross pin 26 projecting on opposite sides of the shaft. At opposite ends of cross pin 26 there are mounted rotatably a pair of coupling bevel gears 27 and 28, which are retained on the cross pin by snap rings 29 and 30, respectively. The bevel gears 27 and 28 both mesh with driving bevel gear 1,4 and are rotatableabout cross pin 26, which extends perpendicular to the axis of rotation of the driving bevel gear 14.

At the opposite side of the coupling bevel gears 27 and 28 there is provided a driven bevel gear 31 mounted loosely on shaft 13 to rotate freely thereon. Gear 31 meshes with both of the gears 27 and 28. An enlarged hub 32, cross drilled to pass the lcross pin 26, is mounted loosely on shaft 13 and serves as a spacer limiting the movement of bevel gears 14 and 31 toward one another. Integral with the driven bevel gear 31 is a spur gear 33 which drives a spur gear 34 mounted on output shaft 35.

Operation In the operation of this mechanism, to drive the output shaft 35 in the forward direction (counterclockwise; Figures l and 2), the electromagnet 23 is maintained de-energized. Therefore, coil spring 21 maintains the friction disk 16 carried by armature 17 tightly against the friction disk 15 carried Vby input gear 12. Since shaft 13 is connected by cross pin 20 to rotate with the armature, through this frictiony coupling the shaft 13 is rotated in unison with, and in the same direction as, input gear 12 and driving bevel gear 14, Due to the rotation of shaft 13, the elongated cross pin 26 and the coupling bevel gears 27 and 28 thereon revolve bodily as a unit about the axis of shaft 13.A The bevel gears 27 and 28, which at this time do not rotate about cross pin 26, revolve in unison with driving bevel gear 14 about the axis of shaft 13 and provide a direct coupling from the driving bevel gear 14 vto the driven bevel gear 31, so

that the driven bevel gear is rotated in the same direction, and at thesame speed, as the driving bevel gear 14. The spur gear 33 integral with the driven bevel gear 31 in turn drives spur gear 34 to rotate output shaft 35 in the direction indicated in Figure 1.

To reverse the direction of rotation of the output shaft 35 while the input shaft 10 continues to rotate in the same direction, the e1ectromagnet23 is energized to attract armature 1 7. When this happens (Figures 3 and4), the friction disk 16 carried by the armature moves away from the friction disk carried by input gear 12 and the electromagnet immediately stops the' rotation of arma ture 17 and shaft 13 and holds them against any further rotation as long as the electromagnet remains energized. Due to the stopping of shaftdlithe. elongated cross pin 25 and the bevel gears 27 and 28 thereon cease to revolve about the axis of shaft 13. The rotation of the driving bevel gear 14, which is integral'with input gear 12, causes the bevel gears 27 and 28 to rotate about the now stationary cross pin 26. Gears 21 and 28 in turn drive the driven bevel gear 31 in a direction opposite tothe direction of rotation of the driving bevel gear 14 and at tbe same speed as the driving bevel gear. Through spur gears 33 and Y34 the output shaft'35 is Adriven from the driven bevel gear 31 in the'reverse direction.

The foregoing mechanism', because of the low inertia of its reversing parts, has been found in practice to be capable of completely reversing the drive to the output shaft within an interval of about .015 second.

It is to be understood that, while there has been disclosed a preferred embodiment of the present invention in the foregoing description and the accompanying drawing, various modifications, omissions and refinements which depart from the disclosed embodiment may be adopted without departing from the spirit and scope of this invention.

We claim:

l. A reversible drive, comprising a rotatable shaft, a rotary driving bevel gear mounted rotatably on said shaft coaxial therewith and extending around the shaft, a cross pin carried by said shaft perpendicular thereto and projecting on opposite sides thereof, a pair of coupling bevel gears carried by said cross pin on opposite sides of the shaft to revolve bodily with said cross pin about the axis of the shaft when the shaft rotates, each of said coupling bevel gears being rotatable about said cross pin, a rotary driven bevel gear mounted rotatably on said shaft coaxial therewith and extending 'around the shaft, both of said coupling bevel gears meshing with both said driving and driven bevel gears, and selective means, including a clutch acting between said driving gear and said shaft, operable to couple said driving gear to said shaft to rotate said shaft in the same direction as said driving gear and cause said coupling gears to revolve about the axis of said shaft in unison with the rotating driving gear to form direct couplings from said driving gear to said driven gear to rotate the driven gear in the same direction as the driving gear'or alternatively to decouple said shaft from said drivingk gear and hold said shaft against rotation to render said cross pin stationary while said coupling gears are rotated about the cross pin by the driving gear to impart a drive vfrom the driving' gear to the driven gear which rotates the driven gear in the reverse direction from theV direction` of rotation of the driving gear.

2. A reversible drive, comprising a rotatable shaft, al

rotary driving bevel gear mounted rotatably on said shaft coaxial therewith and. presenting at one end a toothed bevel face which` extends around' the periphery' of the shaft, a rst friction disk carried by said driving bevel gear at its opposite end, an armature mounted reciprocably on said shaft adjacent said opposite end of the driving bevel gear and connected' to said shaft for rotation in unison therewith, a second friction disk carried by said armature in confronting relation to said first friction disk and positioned to engage said lirst friction disk in one position of the armature on the shaft, a spring biasing the armature to position said second friction disk tightly against said first friction disk to clutch the armature to said driving bevel geart'o thereby couple said shaft to said driving bevel' gean'fo'r rotation therewith, an` electromagnet energizableto'` attract' the armature against the bias of. said spring tohold saidarrngtu're and said shaftl against rotation and to separate said friction disks and thereby disconnect the coupling from said driving bevel gear to said shaft, a rotary driven bevel gear mounted rotatably on said shaft coaxial therewith and presenting a toothed bevel face which extends around the periphery of the shaft `in spaced confronting relation to the toothed bevel face on the driving bevel gear, a cross pin carried by said shaft perpendicular thereto and projecting on opposite sides of the shaft between the toothed bevel faces on the driving and driven bevel gears, a pair of coupling bevel gears carried by said cross pin on oppositev sidesV of said shaft to revolve bodily` with said cross pin about the axis of said shaft when said shaft rotates, each of said coupling bevel gears being mounted rotatably on said cross pin for rotatin thereabout, both of said coupling bevel gears meshing with both said driving bevel gear and said driven bevel gear, said spring when the electromagnet is de-energized positioning. said second friction disk tightly against said rs't friction disk to couple said shaft to said driving gear to rotate said shaft from said driving gear in the same direction and cause said coupling gears to revolve. about the axis of said shaft in unison withsaid driving gear to provide a direct coupling from the driving gear to the driven gear to rotate the driven gear in the saine direction as the driving gear, and saidY electromagnet when energized attracting said armature to holdsaid armature and said shaft against rotation and to separate the friction disks and thereby disconnect the coupling from the driving gear to said shaft, thereby maintaining said shaft andsaid cross pinstation'ary sothat the rotation of the' driving. gear rotates thej coupling gears about said cross pin to drive the driven gear in the` opposite direction from the driving gear.

3. A reversible drive, comprising, in combination, a rotatableshaft, a rotary driving' bevel gear mounted freely on said shaft for rotation about the axis of the: shaft and extending around the shaft, means for rotating said driving Vgear in one direction, means selectively coupling said driving gear to said shaft or disconnecting saidfdriving gear from said shaft and holding said shaft against rotation, a rotary driven bevel gear mounted freely on said shaft for rotation about the axis of the shaft and extending around the shaft in spaced confronting relation to said driving bevel. gear, and a coupling bevel gear having a connection to' said shaft to revolve aboutl the axis of the shaft when the shaft rotates and disposed between the driving and driven gearsand meshingwith both the' driving gear and the driven gear to couple the driven gear directly to the driving gear for rotation in unison therewith when the driving gear is' coupled to said shaft and to drive the driven gear from the driving gear inthe re-v verse direction when said shaft is held` against rotation and is disconnected from the driving gear.

4. The combination of claim 2, wherein said coupling vbevel gears are mounted freely on said cross pin to adjustably engage the beveled tooth faces on the driving and driven gears, and wherein there are provided snap rings on the cross pin adjacentA either' of its ends to retain the coupling bevel' gearson the cross' pin.Y

5. The combination of claim 2, wherein there are additionally provided an input spur gear attached to' the driving bevel gear between the toothed bevel face thereon and 'saidrst friction disk, drive input means' meshing with said input gear to impart rotation to the driving'bevel gear, and an output spur gear attached to said driven" bevel gear in spaced relation lfrom the toothed bevel face thereon. w A

6. A reversible drive comprising' a rotatable shaft, a rotary driving bevel gear mountedV rotatably` on said shaft coaxial therewithl and presenting'a toothed bevel face which extends around the periphery Iof the shaft, a rotary driven bevel gear mounted rotatably' on said shaft coaxial therewith and presenting a toothed bevel face which extends around the" periphery of theshaft 1n` spaced confronting relation to the toothed bevel face on said driving gear, a cross pin carried by said shaft perpendicular thereto and located on opposite sides of the shaft between the toothed bevel faces on the driving and driven bevel gears, a pair of coupling bevel gears carried by said cross pin on opposite sides of the shaft to revolve bodily with the cross pin about the axis of the shaft when the shaft rotates, each of said coupling bevel gears being rotatable on the cross pin and each meshing with the toothed bevel faces on the driving and driven bevel gears, and selective means, including .a clutch acting between said driving gear and said shaft, operable selectively to couple said driving gear to said shaft to rotate said shaft in the same direction .as said driving gear and cause said coupling gears to revolve about the axis of said shaft in unison with the rotating driving gear to form direct couplings from said driving gear to said driven gear to rotate the driven gear in the same direction as the driving gear or alternatively to decouple said shaft from said driving gear and hold said shaft against rotation to render said cross pin stationary while said coupling gears are rotated about the cross pin by the driving gear to impart a drive from the driving gear to the driven gear which rotates the driven gear in the reverse direction from the direction of rotation of the driving gear.

7. A reversible drive comprising, in combination, a rotatable shaft, a rotary driving bevel gear mounted rotatably on said shaft coaxial therewith and presenting a toothed bevel face which extends around the shaft, means for rotating said driving bevel gear in one direction, selective means coupling said driving bevel gear to said shaft or alternatively disconnecting said driving bevel gear from said shaft and holding said shaft against rotation, a rotary driven bevel gear mounted rotatably' on said 'shaft coaxial therewith and presenting a toothed bevel face which extends around the shaft in spaced confronting relation to the toothed bevel face on the driving bevel gear, a cross pin carried by said shaft extend-- ing perpendicular thereto and projecting on oppositel sides of the shaft between the toothed bevel faces on the driving and driven bevel gears, a pair of coupling bevel gears mounted rotatably on said cross pin on opposite sides of the shaft and each meshing with the toothed bevel faces on the driving and driven bevel gears to couple the driven gear directly to the driving gear for rotation in unison therewith when the driving gear is coupled to said shaft and to drive the driven gear from the driving gear in the reverse direction when said shaft is held against rotation and is disconnected from the driving gear.

References Cited in the le of this patent UNITED STATES PATENTS 1,830,941 Hild Nov. 10, 1931 2,209,980 Johnson Aug. 6, 1940 2,347,099 Gridley Apr. 18, 1944 2,464,129 Goettisheim Mar. 8, 1949 FOREIGN PATENTS 342,379 Germany Oct. 17, 1921 583,119 Great Britain Dec. 10, 1946 

